1. Field of the Invention
The present invention relates to an earth drilling device having a rotary drive and a drilling head connected to the rotary drive via a shaft.
2. Description of the Prior Art
For local earth excavation, especially in cases in which there is only very little excavation room, manual tools such as shovels, pickaxes and so-called universal joint shovels with two shovel blades designed with a joint to grasp the earth are used.
Moreover, the state of the art are drills which have correspondingly dimensioned spindle drilling heads and which perform vertical excavation based on Archimedes' principle. Such type motor-driven devices are heavy and expensive.
U.S. Pat. No. 7,185,720 describes a manual drill for local earth excavation which has a suction line connected to a vacuum source. The pipe is surrounded in axial direction by four sturdy longitudinal rods. The bottom ends of the rods taper to a point as a scraping tool. The suction pipe end is disposed at a distance opposite the scraping tools and is able to correspondingly vacuum off the earth loosened by the longitudinal rods through the suction line. The rod ends opposite the tapering scraping tools run into handle-like designed cross struts which permit manual handling of the drilling tool.
U.S. Pat. No. 5,535,836 describes a drilling device for drilling bore holes in the earth. The device is provided with an external pipe connected to a vacuum source which is provided with a saw-toothed structure at the end of the pipe facing the earth. An internal pipe is borne in the interior of the external pipe in a manually or motor driven rotatable manner which is provided with at least one outlet nozzle for a preferably liquid or gaseous material flow by means of which the earth material can be loosened. The loose and broken off earth material is correspondingly removed by the vacuum applied along the external pipe.
Moreover U.S. Pat. No. 3,554,293 describes a device for weeding and edging, in particular, lawn surface. The device is provided at the end of a motor-driven shaft with a cutting tool which is surrounded by a can-like designed protective case. Close to the surface material removal is realized by lowering the cutting tool relative to the protective case.
DE 25 30 531 C2 describes a rotatable drilling tool for earth drilling machines in which the earth loosened by a drilling tool attached to the end of a rotatably borne shaft, is conveyed to a pail-like container disposed downstream along the shaft. When the container is full, the drilling tool closes the pail that is otherwise designed open at the bottom. In this manner the loosened earth can be removed in portions from the thereby produced hole.
Earth excavation using an earth-hole cutter according to DE 203 01 785 U1 occurs according to a similar principle. In the DE 203 01 785 U1 a container designed open at the bottom is also filled with loosened earth by vertically lowering a drilling tool. The earth however is pressed so compact inside the container that the container can be removed vertically from the earth hole.